LU-12166 test: fix broken detection on ZFS

LU-12166 test: fix broken detection on ZFS

We intent to run the command on mds, otherwise
project quota will never be tested.

Test-Parameters:trivial fstype=zfs
Fixes: a046e87 ("LU-7991 quota: project quota against ZFS backend")
Change-Id: I8650a0e1065f0bb465da01556472d3d23b22a530
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Reviewed-on: https://review.whamcloud.com/34609
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-by: Gu Zheng <gzheng@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>